Our collaborative group has developed retroviral and adeno-associated viral vectors containing hairpin ribozymes targeted against HIV-1. Previous experiments showed that T-lymphocytes transduced with retroviral vectors carrying this ribozyme were resistent to the challenge to HIV. A clinical trial is concurrently developed and implemented using transduced T-cells for patients with HIV-infection. As the white blood cells represent direct targets by HIV-1 and as they are all derived from hematopoietic stem cells, transduction of the stem cells from HIV-1 infected individuals might represent a more durable treatment strategy than transduction of T-lymphocytes. Moreover, peripheral stem cells are capable of self-renewal, proliferation and differentiation and the effects of transduction might be magnified in the process. In this trial, the relative merits of CD34+ cells and their subsets from mobilized peripheral blood and from placental and umbilical cord blood gene transductions are examined. In close collaboration with the other Project Leaders, we will conduct preclinical testing of novel vectors for use in CD34+. Based on the experience in conducting the clinical trial using CD4+ cells as targets for delivery of ribozyme therapy, this project represents a logical continuation in developing and implementing a clinical trial using autologous CD34+ cells as targets for delivery of anti-HIV-1 ribozyme. The specific aims are: 1. To optimize the conditions for retroviral mediated gene transduction of anti-HIV-1 hairpin ribozyme into CD34+ cells and their subsets. 2. To determine the transduction and expression efficiency using AAV vectors as compared to retroviral vectors. 3. To quantitavely determine the ability of growth factors to mobilize CD34+ cells and their subsets from HIV-1 infected individuals. 4. To develop and implement clinical protocols for the use of autologous CD34+ cells for delivery of anti-HIV-1 ribozyme genes.